Checkerwork construction



April 1940- E. s. WHELPLEY 2,196,882

CHECKERWQRK CONSTRUCTION Fill! April 4/1939 3 Sheets-Sheet 2 INVENTOR. H6 6 EARL G Wan/=45).

BYJMMWM ATTORNEY April 9, 1940. E. s. WHELPLEY CHBCKERWGRK GONSTRUGTION INVENTOR. EARL G Wan/=45) M M '4 WM ATTORNEYJ.

3 Sheets-She'et 3 Filod April "4, 1939 Patented Apr. 9, 1940 UNITED STATES PATENT OFFICEL CHECKERWORK CONSTRUCTION Earl G. Whelpley,Parma, Ohio, assignor to The Shea-Whelpley Construction Company, Cleveland, Ohio, a corporation of Ohio Application April 4 1939, Serial'No. 265,948

3 Claims. (Cl. 263--51) This invention, relates to refractory checkerwork construction for use in regenerators and, while not necessarily limited thereto, is-particularly adapted,

5 herein, for use in regenerators of the type known as hot blast stoves of the type having a central combustion chamber and circular concentric walls of checkerwork brick surrounding the said combustion chamber and serving to heat regeneratively the air which is used in blast fur- 'naces.

As is well known to those skilled in the art relating to such hot blast stoves, the checkerwork is subjected to severe expansion and contraction strains due to the alternate heating and cooling of the checkerwork whereby, unless proper precautions are taken, a warping and weaving of the checkers will occur resulting frequently in the shifting of the checkers, the dis- 20' tortion and deformation of the checkerwork, and the development of cracks and other defects in the checkerwork to an extent that seriously reduces its efiiciency and stability.

. In my Patent No. 1,715,969, issued June 4, 1929,

35 there is shown a checkerwork construction wherein the checker bricks are substantially T-shaped in outline comprising each a base with a centrally arranged stem or midfeather, the sides of the bases converging towardthe longg, gitudinal central axis of a stove of the type shown herein. .However, the sides of the bases of the checker bricksin only the innermost and outermost walls of the checkerwork shown in the drawings of the said application coincide with -5. radial planes intersecting at the longitudinal central axis of the stove. I The intermediate walls are shown as made up'from bricks identical with those in the innermost wall. It has been found that, when checkerworks have been built ninto hot blast stoves in accordance with the teachings of the aforesaid patent, the sides of the bases of adjacentbricks contact fully only in the innermost and outermost courses; and that the sides of the bases of the bricks in the inter- 5- mediate walls donot contact except at their extreme outer ends, thus providing open V-shaped joints between the sides of the bases of adjacent bricks in said intermediate-walls. Due to this lack of complete contact between the, sides of 5'0 the bases of the bricks in the intermediate walls,

it is impracticable to produce a wellaligned and a well compacted checkerwork, thereby enabling the strains referred to hereinbefore toproduce a partial'twisting or partial shifting of the indi- 5'ividual bricks with relation to thosefl adjacent in" the embodiment illustrated thereto. While this defect could be remedied by designing, for each circular wall, bricks having a true radial convergence of the sides of the bases thereof, such procedure would be prohibitive from the standpoint of cost.

One of the objects of my invention is to provide a construction of checker bricks and an arrangement of the same in the wallsthereof which will permit me to secure substantially complete contact between the sides of thebasesof the adjacent bricksin all of the said walls and with the necessity for manufacturing-a minimum number of diiierent styles of bricks. wherein the bricks of one style diifer fromthose in another only in the degree of convergence of the sides of the bases thereof.

Another object of the invention is to provide checker bricks all having the same width of'base and which can be capable of assembly, not only in the manner set forth hereinbefore, but which will enable each course in each of the concen-. tric walls to be completely. filled with an integral or whole number of bricks.

A checkerwork built in accordance with my invention will also provide aflmaximum-heating 5 surface and a maximum heat-absorbing and heat-storage capacity while possessing ample structural strength to carry the loads and resist the stresses imposed thereupon, Furthermore, i

it will possess a securely interlocked and well 3 nested structure'cap'able of withstanding efiectively any warping, weavingand shifting due to the repeated expansion'and contraction incident to the operation of the. stove in which the checkerwork is installed.v f I g I accomplislithev foregoing objects and other and more limited objects which will'appear hereinafter in and through the construction and ar rangement of parts shown in the accompanying drawings, wherein Fig. 1 is a vertical axial sec- 4 tion' through a 'typicalcenter-combustion hot blast stovein which checker bricks and checkerwork made in accordance withmy invention may be utilized; Fig. '2 is a transverse sectional view taken on the line 2-2 of Fig. 1, looking in the direction of the arrows; Fig. 3 is a side eleva-' tion, Fig. 4 a front'elevation, and Fig. 5a plan view, of one of my improved-checker bricks or checkers; Fig. 6 is a plan View. of a checker brick similar tothat illustrated inFigsr3-5, butdifiering therefrom slightly, in respect to the angle-of convergence of the sides of the base thereof; Fig. 7 is a plan view of another checker brick, similarto those shown in Figs. 3-6 inclusive, but differmg therefrom slightly in-respectto the angleof g erwork; Fig.

vided with checker bricks made in accordance with my invention, the intermediate wall being made with checker bricks of the type shown, for instance, in my Patent No. 1,715,969-the tongues and grooves (to be described hereinafter) being omitted for the sake of clearness of illustration; Fig. 9 is an enlarged detail in horizontal section through a portion of the hot blast stove shown in Fig. l and including the wall of the combustion chamber, the outer wall and jacket of the hot blast stove, and the interposed check- 10 is a typical vertical section through the portion of the stove illustrated in Fig. 9; Fig. 11 is an enlarged sectional view through a portion of one of the courses of checker bricks showing the manner in which the sides of the base portions of adjacent bricks are interlocked; and Fig. 12 is a fragmentary sectional view corresponding to the line l2-l2 of Fig. ll, looking in the direction of the arrows and illustrating the top and bottom interlocking means with which the checker bricks are provided.

Referring more particularly to Figs. 1 and 2 of the drawings, 1 denotes the outer cylindrical metallic shell and 2 the central combustion chamber of a hot blast stove having the checkerwork 3 interposed between the combustion chamber and the jacket wall 4, with a dome 5 and a support 6 for the checkerwork, the stove being provided with a bottom 1 which is adapted to sup port the structure superimposed thereupon.

The stove bottom is provided with a passage 8 which serves alternately as a gas inlet and a hot blast outlet. Thebottom is also provided with an opening 9 through which products of combustion may be delivered to the chimney; and it is also provided with the usual opening (not shown) for the cold blast. Heat insulating material H1 is interposed between the shell I and the jacket wall 4. It will be understood that the standard valves and fittings will be provided for enabling the stove to cooperate with a blast furnace; but these are omitted since they are well known to those skilled in the art and form no part of the present invention.

The support for the checkerwork, which is indicated at 6, must be of suitable size, conformation and construction to enable it to realize its function. A construction of support suitable for this purpose is disclosed in my Patent No.

"- 1,438,349, issued December 12, 1922.

I am able to construct a checkerwork such as disclosed in Figs. 9 and 10 with the use of only the three styles of checker bricks shown in Figs. 3-7, inclusive, the bricks in the said styles being identical except for the comparatively slight differences referred to hereinbefore and which will be pointed out in connection with the discussion of the said figures. It will be noted that each of these bricks is generally T-shaped in plan, comprising each a base H and a midfeather or stem I2 projecting centrally from the inner face of the base. The outer face [3 of the base of each of these bricks may be arcuate, or fiat and smooth (as shown). The innerspaced faces M of the base are also preferably flat, smooth, and parallel with the outer faces Hi. The face I5 at the inner end of each of the stems or midfeathers I2 is also preferably fiat,

smooth, and parallel with the outer face I3 of its base. The greatest width of the base of each of the bricks is at its back or outer face l3, the width of the said faces being indicated at w. The dimension of each brick from the back l3 thereof to the free or inner end of the stem is indicated at (1. Due to the fact that the backs l3 are flat or plain, instead of being curved, this dimension also coincides with the distance from the center of the back to the center of the free end of the stem or midfeather. The upper face i5 of each checker is preferably flat and square with the faces 13, M and I5; and a rib or tongue l! is shown as formed on the upper face 16 of each brick, the said tongue being centrally disposed with reference to the stem or midfeather and being substantially coextensive in length therewith. The lower face l8 of each brick is generally flat and parallel to the upper face It; and a depression or groove I9 is formed in the face of the midfeather, being preferably centrally disposed with reference to the stem l2 and of substantially the same length as the stem and being complementary to the rib or tongue [1.

The side faces 2% and 2| of the bases of the checkers are also substantially flat and converge slightly from the outer faces l3 toward the midfeathers or stems. The faces 20 are shown as provided each with a centrally located rib or tongue 22 extending in a vertical direction and the faces 2! are formed each with a centrally located groove extending vertically thereof. Because of irregularities in manufacture, the grooves l9 and 23 are made slightly larger than the tongues l1 and 22, respectively, so that the tongues may enter said grooves without any substantial loose play.

It will be noted that the side faces 20 and 2| of the bases of the bricks A, B and C, shown in Figs. 5, 6 and 1, respectively, converge toward the stems thereof. In the checker-work construction shown in Figs. 9 and 10, the innermost wall is made up of the bricks A and, when the bricks are assembled in said wall, planes including these side faces will intersect at the axial center of the combustion chamber of the stove, whereby the side faces of adjacent bricks in each course of this wall will be in engagement throughout substantially their entire extent. The angle of convergence of the side faces of the backs A is indicated at a in Fig. 5.

The bricks B (Fig. 6) are shown as having been used in building the sixth circular wall; and their side faces 30 and Si lie in planes which intersect each other at the axial center of the combustion chamber so that the side faces of adjacent bricks in each course of this wall will also be in substantial contact throughout their full extent. The angle of convergence'of the side faces of the bricks I3 is indicated at b.

In like manner the bricks C (Fig. '7) are shown as having been employed for building the outermost circular wall; and, when assembled in said wall, their sidefaces 40 and 4| will lie in planes intersecting each other at the axial center of the stove; and the side faces of adjacent bricks in each. course of the outermost wall will also be in, contact throughout substantially their entire-extent. The angle of convergence of the side faces 40 and 4| is indicated at 0.

Because the radial distance of the wall made up entirely of the bricks B from the axial center of the stoveis greater than that made up entirely of the bricks A, the convergence of the side faces of the bricks in the latter wall will be less than the convergence of the side faces in the former wall. For the same reason, the convergence of the side faces of the bricks employed in the outermost wall will be less than that of the side faces of the wall made up entirely of the bricks B.

As pointed out hereinbefore, it is important that the bricks comprising the checkerwork walls of the character described shall have the side faces of their base portions in contact throughout substantially their entire extent, for the reasons set forth. This object could be realized by using in each wall bricks having their side faces lying in planes intersecting each other at the axial center of the stove. However, in view of the fact that hot blast stoves of the type shown herein range in diameter from 21 feet upwards of 24 feet and are provided with from 10 to 16 concentric annular walls, it will be evident that to accomplish this full-area of contact between the side faces of the bricks in the manner just stated would be prohibitive in cost,

because of the necessity for making, stocking,

and handling so many different styles of bricks.

By constructing and assembling the bricks in the manner shown and described herein, I am enabled to produce a stable and accurately fitted checkerwork with the employment of only the three different styles of bricks shown in Figs; 5, 6 and 7. Furthermore, by the selection of a proper spacing between the outer surfaces of adjacent circular walls, I am enabled to utilize in the horizontal courses of all of the circular walls an integral number of bricks, all having the same width of base w. This spacing distance is indicated by the line at on Figs, 5, 6 and '7.

The manner in which I am enabled to build a stable and correctly fitted checkerwork with the limited number of styles of bricks shown in Figs. 5, 6'and 7 is illustrated in Fig. 8, wherein 60 corresponds to a portion of one of the courses of the innermost wall 6!) on Fig. 9; wherein 62 corresponds to a portion of one of the courses of the wall 62 on Fig. 9; and wherein Bo denotes a portion of a course in a wall located between the walls 60 and 62' and made up entirely of the bricks A (which correspond with the bricks A in Fig. 9). It will be noted that all of the bricks in the partial course 60 have their side faces in full contact, the said faces lying in the radial planes indicated by the lines :v:r. It will be noted further that the side faces of adjacent bricks A in the partial course 6!) are not in contact along the radial planes indicated by the lines :r--.r, but are in contact only at their outer ends. It will be evident that the bricks A', when assembled in the manner shown in 80*, will not produce a securely interlocked or well fitted checker work, since the sides of the individual bricks are not firmly supported against the side faces of adjacent bricks. It will be evident further that should the bricks A be used in walls of greater diameter than that including the partial course 69*, the divergence between the sides of adjacent bricks will be correspondingly increased, with a like aggravation of the defect pointed out in connection with the use of the bricks A in the wall including the partial course 60*; and that this divergence will increase progressively with the increase in distance of the walls from the wall including the partial course 60. However, in the partial course 62', I have shown how it is possible to combine the checkers A (corresponding to the checkers A in Fig. with fitted in the courses of other walls.

checkers B (corresponding to the checkers B in Fig. 6) in such manner as to secure substantially complete contact between the side faces of the checkers.

A practical application of the teachings shown in this diagrammatic View appears in Figs. 8 and 9, wherein the innermost wall60 is composed entirely of the bricks A and the wall 65 is composed entirely of the bricks B, while the walls intermediate therebetween are made up of assemblies of varying numbers of bricks A and B, the number of the bricks B increasing progres sively in the said walls from the wall Bl to the wall 64. In like manner, the walls intermediate the wall 65 and the wall 10 (which is made up entirelyof bricks C) are made by assembling the bricks B and C in proper proportions to insure a full face contact between the bricks, the number of bricks C employed in the intermediate walls C increasing progressively from the wall 66 to the wall 69.

In assembling the checkers in the walls 60-10,

. it is preferable that similar checkers be superimposed upon one another as the checkerwork is built up and that the horizontal joints between the checkers in one course of each wall be staggered with respect to those in the courses immediately. adjacent thereto.

In constructing a hot blast stove of the type" referred to herein, the best and most uniform results are obtained by making the checkerwork. of uniform construction; that is to say, by having the fiues of substantially the same size and the flue walls of substantially the same thickness in any transverse plane through the checkerwork. For this reason it is desirable to maintain substantially identical the dimensions of all of the checker bricks. In other words, the width w of the backs of the bases and the dimension d will be made identical in all of the bricks in any particular installation. I

It has been found feasible to design a checker brick having such a width w that an integral number of the same will form a properly fitted complete circular'wall of a predetermined radius: but it has been foundthat, when it has beer.v attempted to use these same bricks in walls hav ing larger orsmaller radii, no integralnumber of checkers can be used in the courses of said walls. Relatively large spaces amounting to as much as seven-eighths of the width of a brick, frequently remain when the bricks are properly After the width of the unfilled space in any such course has been determined, it has been found necessary to re-space all of the bricks in such course, which has resulted in providing excessive spaces between the side faces of adjacent bricks, with the disadvantages pointed out hereinbefore.

An important feature of the present invention is that it makes it possible to fill properly and completely the courses of each of the successive concentric walls of the checkerwork with bricks having substantially identical over-all dimensionsdiffering only in the degree of converhereinbefore; I have found that, having made the dimension w of such extent as to enable bricks having such dimension to be assembled to form a course in one wall wherein all the side faces will be in contact and the checkers will gence of the side faces thereof, as pointed out l completely fill such course, I can, by properly proportioning the dimension d, utilizea definite number of additional bricks, or fewer bricks, which can either be insertedinto the courses of so i walls of progressively increasing radii or be omitted from walls of progressively decreasing radii, and which will still completely fill each course. I have found that this number is a function of the radius of the outer surface of each wall and can be ascertained from the following formula, wherein N represents the number of additional or fewer checkers desired; 10 denotes the width of the back of each checker; and (1 equals the distance between the outer surfaces of adjacent concentric circular walls, said distance being indicated at d in Figs. 3 and 5-7. This equation may be expressed as follows: NW -21rd.

This equation contains three variable quantities, and when values are assumed for any two of these variables, the third can be readily determined. For example, suppose that a brick of suitable width has been formed to completely fill the wall 85 in 9 and that these bricks, when assembled, will form a complete wall of properly fitted bricks, Assume that the width of the checkers is 6%,; inches. Then, if it be assumed that the variation in the number of the bricks in the walls 65 and 64 shall be six, then, by solving the equation, the dimension (1 will be found to be approximately 6% inches. There will be a like increase in the number of closely fitted bricks in each course of each of the successive walls 8?, $8, 69 and ill and a decrease of the same number of bricks in each course of each of the successive walls 63, G2, 8! and 68.

It will be evident from the foregoing description that I am enabled to produce a checkerwork having all of the desirable qualities pointed out hereinbefore and to accomplish the same by the employment of a small number of sizes or dimensions of bricks. It will be evident further that, if desired, the outer faces l3 may be rounded or arcuate instead of flat; also that various changes may be made in the details of construction without avoiding or departing from the spirit of my invention; for instance, variations may be made in the thickness of the bases and of the midfeathers thereby to produce checkerworks having corresponding variations in flue areas and corresponding differences in the bulk or weight of the checkerwork; and these changes may be made without impairing any of the advantages which have been pointed out hereinbefore.

Having thus described my invention, what I claim is:

1. An apparatus of the character described comprising a plurality of circular concentric walls, each wall comprising in turn a plurality of horizontal courses of checker bricks of substantially T shape in plan view and each comprising a base and a centrally located mid-feather or stem, the ends of the mid-feathers or stems in every wall except the innermost wall engaging the back portions of the bricks of the wall next therewithin, the sides of the base of each of said bricks of the innermost wall coinciding substantially with radial planes extending to the center of curvature of said wall; and the outermost of said walls consisting of horizontal courses of bricks similar to the bricks in the first mentioned wall but having the sides of their bases coinciding substantially with radial planes extending to the center of curvature of said walls; the bricks in the walls intermediate the innermost and outermost of said walls comprising combinations of the bricks of which the innermost and outermost walls are composed whereby the sides of the base of each brick in said intermediate walls will be in contact throughout substantially their entire extent with the sides of the bases of the bricks adjacent thereto.

2. An apparatus of the character described comprising an inner circular wall composed of horizontal courses of bricks, each having a base and a centrally located mid-feather or stem, the sides of the base of each of said bricks coinciding substantially with planes extending to the center of curvature of the said wall, a circular wall concentric with and spaced from the first mentioned Wall, and a circular wall concentric with and spaced from the second mentioned wall, there being circular walls interposed between the first and second mentioned walls and concentric therewith and there also being circular walls interposed between the second and third mentioned walls and being concentric therewith; the bricks in the second mentioned wall being similar to the bricks in the first mentioned wall but having the sides of the bases thereof substantially coincident with planes extending to the common center of curvature of the said walls; The bricks in the third mentioned wall being similar to the bricks in the first and second mentioned walls but having the sides of the bases thereof substantially coincident with planes extending to the common center of curvature of the said walls; the walls intermediate the first and second mentioned walls being composed of combinations of individual bricks of the types used in the first and second mentioned walls; and the walls intermediate of the second and third mentioned walls being composed of cornbinations of individual bricks of the types used in the second and third mentioned walls, whereby the sides of the base of each brick in said intermediate walls will be in contact throughout substantially their entire extent with the sides of the bases of the bricks adjacent thereto.

3. In the apparatus set forth in claim 1, the number of bricks of the same width of base which are to be added to each course of a wall immediately surrounding a wall having a known number of bricks in each course thereof and to be subtracted from each course of a wall immediately within and surrounded by the wall having such known number of bricks in each course thereof being determinable by the equation Nwz21rd wherein N equals the number of bricks to be added or subtracted, w equals the width of the base of each brick, and cl equals the shortest distance from the back of each brick to the free or unattached end of its mid-feather or stem at a point substantially midway between the sides thereof.

EARL G. WHELPLEY. 

